I have been using an external SSD as my primary drive on my iMac for over a year. I'm not sure if it got unplugged or nudged while powered up but it now doesn't work. I can mount the drive but I get errors when trying to mount the main partition.
I have followed advice given here:
however none of the solutions have had much effect.
Looking at my partition list I see that the partition type and name for my main partition is screwy:
/dev/disk4 (external, physical): #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *275.1 GB disk4 1: EFI EFI 209.7 MB disk4s1 2: 7C3457EF-0000-11AA-AA11-00306543ECAC 274.9 GB disk4s2
I presume that they should be "Apple_Boot" and "Macintosh HD".
I had hoped that using
sudo asr adjust --target /dev/disk4s2 -settype "Apple_Boot"
would do the trick (or at least help) but all I get is
asr: Volume adjustment failed: Invalid argument
and as there appears to be very little documentation on the "adjust" functionality of asr I don't know how to proceed. I bought a new drive and hoped to restore my data from a Time Machine backup but it turns out that's corrupted!! So, I really do need to try and get this drive back into action again. Any help would be hugely appreciated.
Drive was running OSX 10.14.3 Mojave.